Ultra-Selective CMSMs Derived from Resorcinol-Formaldehyde Resin for CO₂ Separation

Area of Science:

• Materials Science
• Chemical Engineering
• Membrane Technology

Background:

• Carbon Molecular Sieve Membranes (CMSMs) are crucial for gas separation, particularly CO2 capture.
• Optimizing CMSM performance requires precise control over precursor synthesis and post-treatment conditions.

Purpose of the Study:

• To synthesize and optimize CMSMs derived from a resorcinol-formaldehyde precursor for enhanced CO2/N2 separation.
• To investigate the impact of polymerization degree and oxidative post-treatment on membrane performance.

Main Methods:

• Synthesis of resorcinol-formaldehyde precursor for CMSMs.
• Gel Permeation Chromatography (GPC) for degree of polymerization analysis.
• Oxidative post-treatment under controlled temperature, pressure, and oxygen concentration.
• Gas permeation tests and Pore Size Distribution (PSD) analysis via perm-porometry.
• Surface morphology analysis using 3D laser confocal microscopy.

Main Results:

• The R80 membrane, polymerized at 80°C, showed promising preliminary performance.
• Optimized post-treatment (100 min, 6 bar, 120°C, 10% O2) significantly enhanced CO2 permeance and CO2/N2 selectivity.
• The optimal CMSM (R80T100) achieved a CO2/N2 ideal selectivity of 194 at 100°C with a CO2 permeability of 4718 Barrer.
• Post-treatment reduced surface roughness and confirmed the optimal treatment duration.

Conclusions:

• The developed CMSM (R80T100) demonstrates superior performance exceeding the Robeson's upper bound for polymeric membranes.
• The study highlights the critical role of controlled polymerization and oxidative post-treatment in tailoring CMSM properties for efficient CO2 capture.